1. Field of the Invention
The present invention relates generally to computer systems having a graphical user interface. More particularly, the invention pertains to a method and apparatus for defining and connecting graphical objects to one another in an object oriented computing environment.
2. Description of the Prior Art
Graphical user interfaces employing an object-oriented programming paradigm are commonly used in application programs such as word processing and database programs, as well as other graphic desktop applications. A graphical user interface provides manipulable graphical objects such as icons, windows, and various controls that can be used to control underlying software or hardware represented by the graphical objects. Typically, a user interacts with the graphical user interface using a graphical pointer that is controlled by a pointing device, such as a mouse or trackball, to accomplish conventional drag and drop techniques and other graphical object manipulations.
The conventional object-oriented, graphical user interface provides an effective manner to monitor and control underlying components represented by the graphical objects. However, applications that display animation or graphical movement between connected components have required the assistance of computer programmers and specially designed custom software. Examples of such applications are computer simulation programs, mechanical emulation programs, and user display or control applications that graphically display moving components of an automated process. Accordingly, these programs are typically difficult and expensive to develop making them generally unavailable to many industries and possible applications.
As will be described in greater detail hereinafter, the method and apparatus of the present invention solves the aforementioned problems by employing an object oriented paradigm to represent connectable graphical objects and employs a number of novel features that render it highly advantageous over the prior art.
Accordingly, it is an object of this invention to provide a system and method for connecting and manipulating graphical objects.
Another object of this invention is to provide an improved graphical user interface in a computer system for displaying or monitoring graphical objects.
Still another object of this invention is to provide object dragging and dropping techniques for connecting graphical objects.
Yet another object of this invention is to provide a method and apparatus which can be easily used by systems engineers or designers to provide applications having graphical objects virtually connected to one another in a graphical computing environment without having to rely upon the assistance of computer programmers and specially designed custom software.
To achieve the foregoing and other objectives, and in accordance with the purposes of the present invention a method and apparatus of operatively joining graphical objects are provided. The graphical objects are displayed on a computer display device of a computer system which includes the display device, a processor, and memory for storing the graphical objects.
At least two graphical objects are connected or anchored to one another such that movement of a representation of one of the graphical objects on the display device correspondingly affects the movement of a representation of the other graphical object. In use, the representation of one of the graphical objects will be moved on the display device in response to a value change of a property of that graphical object, where that property is associated with the positioning of the representation of that graphical object on the display device. The representation of any connected graphical object joined therewith will then move automatically so that the representations of the graphical objects preferably emulate a mechanical connection.
In accordance with an aspect of the invention, the graphical objects are displayed by dragging representations of the graphical objects in response to position commands from a user interface coupled with the computer system to position the representations in a desired orientation relative to one another. Each graphical object is connected to another at an anchor point that can also serve as a pivot point to move the graphical object pivotally about the other.
Other objects, features and advantages of the invention will become more readily apparent upon reference to the following description when taken in conjunction with the accompanying drawings, which drawings illustrate several embodiments of the invention.